Hi Thanh - I see your point, but I didn't think that was a good idea in a bigger model (loved your little engine) though. I don't know how you did the graphics to the photo, but you made it look pretty good. I will send another photo next couple of days as I have now moved the radiator away from the heat and is now placed on top of the water pump. Looks enormous now!I found another problem as well - the displacer was out of alignment and jamming against one side. Have to straighten that one out.

Hi youarenotwelcome friend. Due to this model being a diaphragm type I don't think you can make one to do 10kW. You would need one huge engine that would need to pressurized with helium or hydrogen to get a better dense atmosphere. The model I have shown will do to around 4 to 6inch max.Hope this helps with your endeavour. Trevor

You would only need to raise the radiator 75 mm to 100 mm, to just under where the pump is.one thing I would redesign is the crankshaft mounting, first the bearings should be as close as possible to the crank webs, then the over hang out to the pulley needs support, maybe a bearing between the gear and the pulley, or if you decide not to use the pump, shorten the shaft. With the long shaft the will be some flex which causes friction in the bearings.This is the second motor that I built in 1994, it's still running, although it needs a new hot cap, after a good few hundred hours of running its just about stuffed.Ian S C

Wow! Nice one Ian. That is a superb engine. I see your point about the radiator and shaft length, but I am stuffed now the way I have set it up on the crankshaft. I will use this engine for trials of different ways as the base and top plates have holes drilled all over it. I have just come back from the shed after raising the radiator and making a new displacer with all SS. When I ran it this time with the heat on moderate (with all the gear attached and the fan) the engine fired into life and went so well it got the shakes bad as the rpm was up to the 800+ revs. Nice cool breeze was coming from the fan though. I also broke the alignment support. AH Well! a learning Experience. I do like the diaphragm though - it has done around 15 hours work now and still looks good and strong. Must be good Chinese tyre rubber hee hee hee!!!

Good one Trev. They usually have a certain band of revs that they run smoothly.Re the photo: Power piston cast iron, power cylinder steel water pipe. Hot cap 316 stainless steel, displacer, thin wall mild steel. Maximum 2100 rpm, normal working 600/800 rpm. Total time run over 1000hrs.Ian S C

That's some high revs there Ian. I like your idea of using steel water pipe for the power piston. I certainly will be using bronze as my next cylinder for another venture so will use water pipe as the piston one that one. I hope I can get to that mark of a 1000 revs with thermal water cooling and a genset of a couple watts. I now have this diaphragm engine now finished and working well with the radiator on top. I haven't as yet taken the photo as I am busy with my club at present. I'll get there though.Trevor

This is the finished engine now showing the radiator on the top. I finished a display at our gemshow today at Tolga with this engine running for 5 hours non stop in 33 dgree heat. The radiator kept the cooling water quite low and was pleasing to see it not getting over hot at any time. The diaphragm didn't miss a beat, so thumbs up for the diaphragm idea. Trevor

Attachments

Finished Engine after a 5 hour run Rear Side View.jpg (141.42 KiB) Viewed 981 times

Finished Engine after a 5 hour run Front Side View.jpg (146.14 KiB) Viewed 981 times

Trevor wrote:Have just finished the crankshaft and fitted the bearing blocks into their seats.Don't let anyone tell you that crankshafts are easy to make - THEY AREN'T I had a hell of a time getting it straight after silver soldering it. I think there was to many cranks. At least it is done and straight now. Will be fitting the condors next and making the water pump drive including the generator.\Trevor

Hi Thanh - The crank shaft is silver soldered, the pins are 3/16" hardened steel and the main shaft is 1/4" Brass which probably wasn't a good idea as it does flex easily. The brass shanks (side plates) were drilled as straight as I could using 4 jaw chuck, however these can be done on a good drill press. Setting the cranks up is difficult and I did use the system that Ian had shown a bit further back in this post. It was the only way I could do it. I had problems with the brazing as the shaft was long and in the course of brazing it - It bent from the heat. So I had to put it in the lathe (or between two V blocks) and start bending to get straight. Had to use a dial gauge to get it exact or within 0.02 mm. Sorry about using both metric and English but we seem only to be able to get a mix of metals here.Trevor